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Cell - Deciphering and Prediction of Transcriptome Dynamics under Fluctuating Field Conditions

Determining the drivers of gene expression patterns is more straightforward in laboratory conditions than in the complex fluctuating environments where organisms typically live. We gathered transcriptome data from the leaves of rice plants in a paddy field along with the corresponding meteorological data and used them to develop statistical models for the endogenous and external influences on gene expression. Our results indicate that the transcriptome dynamics are predominantly governed by endogenous diurnal rhythms, ambient temperature, plant age, and solar radiation. The data revealed diurnal gates for environmental stimuli to influence transcription and pointed to relative influences exerted by circadian and environmental factors on different metabolic genes. The model also generated predictions for the influence of changing temperatures on transcriptome dynamics. We anticipate that our models will help translate the knowledge amassed in laboratories to problems in agriculture and that our approach to deciphering the transcriptome fluctuations in complex environments will be applicable to other organisms.

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Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps | Annals of Botany | Oxford Academic

Anaesthetics stop diverse plant organ movements, affect endocytic vesicle recycling and ROS homeostasis, and block action potentials in Venus flytraps | Annals of Botany | Oxford Academic | plant cell genetics | Scoop.it

Abstract Background and Aims Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans. Methods A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode. Key Results Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested. Conclusions Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia.

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Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities

Meta-analysis approach to assess effect of tillage on microbial biomass and enzyme activities | plant cell genetics | Scoop.it
Measures of soil biology are critical for the assessment of soil quality under different agricultural management practices. By modifying soil microclimate, tillage exerts the most important control on soil microbial communities. The objective of this study is to assess the effect of tillage on soil microbial biomass and enzyme activities. A meta-analysis was conducted utilizing 139 observations from 62 studies from around the world; the selected effect size (ES) was logn of the response ratio (RR), the mean of the tilled treatment divided by the mean of the no-till control. This ES was calculated for seven different microbial properties – microbial biomass carbon (MBC) and nitrogen (MBN), metabolic quotient (qCO2), fluorescein diacetate (FDA), dehydrogenase (DHA), β-glucosidase, and urease. Microbial biomass, metabolic quotient and enzyme activities were evaluated due their prevalent usage in evaluation of soil quality and use in soil quality indices. Overall, microbial biomass and all of the enzyme activities were greater under no-till compared to tillage. One exception to this was that under chisel tillage, there was no difference in MBC between the tilled plots and no-till. The qCO2 was greater under tillage than under no-till indicating more active microbes in tilled soil, perhaps compensating for the reduced quantity. In contrast, when looking at only long-term experiments, qCO2 was similar under both tillage and no-till, which may indicate that eventually microbes in no-till plots become as active as those in tilled plots even with the larger microbial community. The findings of this study illustrate that no-till and even reduced tillage, such as chisel tillage, promote larger microbial communities and greater enzymatic activity.
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Low number of fixed somatic mutations in a long-lived oak tree

Low number of fixed somatic mutations in a long-lived oak tree | plant cell genetics | Scoop.it

Because plants do not possess a defined germline, deleterious somatic mutations can be passed to gametes, and a large number of cell divisions separating zygote from gamete formation may lead to many mutations in long-lived plants. We sequenced the genome of two terminal branches of a 234-year-old oak tree and found several fixed somatic single-nucleotide variants whose sequential appearance in the tree could be traced along nested sectors of younger branches. Our data suggest that stem cells of shoot meristems in trees are robustly protected from the accumulation of mutations.

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Stable Production of the Antimalarial Drug Artemisinin in the Moss Physcomitrella patens

Stable Production of the Antimalarial Drug Artemisinin in the Moss Physcomitrella patens | plant cell genetics | Scoop.it

Malaria is a real and constant danger to nearly half of the world’s population of 7.4 billion people. In 2015, 212 million cases were reported along with 429,000 estimated deaths. The World Health Organization recommends artemisinin-based combinatorial therapies, and the artemisinin for this purpose is mainly isolated from the plant Artemisia annua. However, the plant supply of artemisinin is irregular, leading to fluctuation in prices. Here, we report the development of a simple, sustainable, and scalable production platform of artemisinin. The five genes involved in artemisinin biosynthesis were engineered into the moss Physcomitrella patens via direct in vivo assembly of multiple DNA fragments. In vivo biosynthesis of artemisinin was obtained without further modifications. A high initial production of 0.21 mg/g dry weight artemisinin was observed after only 3 days of cultivation. Our study shows that P. patens can be a sustainable and efficient production platform of artemisinin that without further modifications allow for industrial-scale production. A stable supply of artemisinin will lower the price of artemisinin-based treatments, hence become more affordable to the lower income communities most affected by malaria; an important step toward containment of this deadly disease threatening millions every year.

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Frontiers | Testing of Auxotrophic Selection Markers for Use in the Moss Physcomitrella Provides New Insights into the Mechanisms of Targeted Recombination | Plant Science

Frontiers | Testing of Auxotrophic Selection Markers for Use in the Moss Physcomitrella Provides New Insights into the Mechanisms of Targeted Recombination | Plant Science | plant cell genetics | Scoop.it
The moss Physcomitrella patens is unique among plants in that homologous recombination can be used to knock out genes, just like in yeast. Furthermore, transformed plasmids can be rescued from Physcomitrella back into E. coli, similar to yeast. In the present study, we have tested if a third important tool from yeast molecular genetics, auxotrophic selection markers, can be used in Physcomitrella. Two auxotrophic moss strains were made by knocking out the PpHIS3 geThe moss Physcomitrella patens is unique among plants in that homologous recombination can be used to knock out genes, just like in yeast. Furthermore, transformed plasmids can be rescued from Physcomitrella back into E. coli, similar to yeast. In the present study, we have tested if a third important tool from yeast molecular genetics, auxotrophic selection markers, can be used in Physcomitrella. Two auxotrophic moss strains were made by knocking out the PpHIS3 gene encoding imidazoleglycerol-phosphate dehydratase, and the PpTRP1 gene encoding phosphoribosylanthranilate isomerase, disrupting the biosynthesis of histidine and tryptophan, respectively. The resulting PpHIS3∆ and PpTRP1∆ knockout strains were unable to grow on medium lacking histidine or tryptophan. The PpHIS3∆ strain was used to test selection of transformants by complementation of an auxotrophic marker. We found that the PpHIS3∆ strain could be complemented by transformation with a plasmid expressing the PpHIS3 gene from the CaMV 35S promoter, allowing the strain to grow on medium lacking histidine. Both linearized plasmids and circular supercoiled plasmids could complement the auxotrophic marker, and plasmids from both types of transformants could be rescued back into E. coli. Plasmids rescued from circular transformants were identical to the original plasmid, whereas plasmids rescued from linearized transformants had deletions generated by recombination between micro-homologies in the plasmids. Our results show that cloning by complementation of an auxotrophic marker works in Physcomitrella, which opens the door for using auxotrophic selection markers in moss molecular genetics. This will facilitate the adaptation of shuttle plasmid dependent methods from yeast molecular genetics for use in Physcomitrella.
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Genome sequence of the progenitor of the wheat D genome Aegilops tauschii

Genome sequence of the progenitor of the wheat D genome Aegilops tauschii | plant cell genetics | Scoop.it

Aegilops tauschii is the diploid progenitor of the D genome of hexaploid wheat1 (Triticum aestivum, genomes AABBDD) and an important genetic resource for wheat2,3,4. The large size and highly repetitive nature of the Ae. tauschii genome has until now precluded the development of a reference-quality genome sequence5. Here we use an array of advanced technologies, including ordered-clone genome sequencing, whole-genome shotgun sequencing, and BioNano optical genome mapping, to generate a reference-quality genome sequence for Ae. tauschii ssp. strangulata accession AL8/78, which is closely related to the wheat D genome. We show that compared to other sequenced plant genomes, including a much larger conifer genome, the Ae. tauschii genome contains unprecedented amounts of very similar repeated sequences. Our genome comparisons reveal that the Ae. tauschii genome has a greater number of dispersed duplicated genes than other sequenced genomes and its chromosomes have been structurally evolving an order of magnitude faster than those of other grass genomes. The decay of colinearity with other grass genomes correlates with recombination rates along chromosomes. We propose that the vast amounts of very similar repeated sequences cause frequent errors in recombination and lead to gene duplications and structural chromosome changes that drive fast genome evolution.

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Persulfidation proteome reveals the regulation of protein function by hydrogen sulfide in diverse biological processes in Arabidopsis | Journal of Experimental Botany | Oxford Academic

Persulfidation proteome reveals the regulation of protein function by hydrogen sulfide in diverse biological processes in Arabidopsis | Journal of Experimental Botany | Oxford Academic | plant cell genetics | Scoop.it
Hydrogen sulfide-mediated signaling pathways regulate many physiological and pathophysiological processes in mammalian and plant systems. The molecular mechanism by which hydrogen sulfide exerts its action involves the post-translational modification of cysteine residues to form a persulfidated thiol motif, a process called protein persulfidation. We have developed a comparative and quantitative proteomic analysis approach for the detection of endogenous persulfidated proteins in wild-type Arabidopsis and L-CYSTEINE DESULFHYDRASE 1 mutant leaves using the tag-switch method. The 2015 identified persulfidated proteins were isolated from plants grown under controlled conditions, and therefore, at least 5% of the entire Arabidopsis proteome may undergo persulfidation under baseline conditions. Bioinformatic analysis revealed that persulfidated cysteines participate in a wide range of biological functions, regulating important processes such as carbon metabolism, plant responses to abiotic and biotic stresses, plant growth and development, and RNA translation. Quantitative analysis in both genetic backgrounds reveals that protein persulfidation is mainly involved in primary metabolic pathways such as the tricarboxylic acid cycle, glycolysis, and the Calvin cycle, suggesting that this protein modification is a new regulatory component in these pathways.
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“La Vie en Rose”: Biosynthesis, Sources and Applications of Betalain Pigments

“La Vie en Rose”: Biosynthesis, Sources and Applications of Betalain Pigments | plant cell genetics | Scoop.it

This review discusses betalain metabolism in light of recent advances in the field, with an up-to-date survey of characterized genes and enzymes that take part in betalain biosynthesis, catabolism and transcriptional regulation. Currently-used and potential new sources for betalains are discussed, together with a summary of possible applications of betalains in research and commercial use.

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Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome, cell

Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome, cell | plant cell genetics | Scoop.it
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Via Loïc Lepiniec
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Corporate Concentration and Technological Change in the Global Seed Industry

Corporate Concentration and Technological Change in the Global Seed Industry | plant cell genetics | Scoop.it
In the past three decades, the seed sector has experienced, and is now again experiencing, corporate concentration trends. The fallout of this consolidation is the subject of numerous concerns. However, the seed sector is rather poorly understood. Thus, it is useful to understand it better and to investigate the potential impact on the agri-food chain of the trend toward increased corporate concentration. The first part of this paper presents the main characteristics of the global seed sector, its stakeholders, and its size in the agri-food chain. Next, the corporate consolidation trends of the seed industry over the past two years are examined. The technological evolution of the seed sector is also briefly presented. In the last part of this paper, the fallout of recent mergers and acquisitions in the seed industry are analyzed. Opposing views are expressed on the impact of these mergers and acquisitions in the agri-food chain: while certain stakeholders worry about the risk of food power by the biggest companies, some others expect useful innovations.
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Frequent paramutation-like features of natural epialleles in tomato

Freakish and rare or the tip of the iceberg? Both phrases have been used to refer to paramutation, an epigenetic drive that contravenes Mendel's first law of segregation. Although its underlying mechanisms are beginning to unravel, its understanding relies only on a few examples that may involve transgenes or artificially generated epialleles. By using DNA methylation of introgression lines as an indication of past paramutation, we reveal that the paramutation-like properties of the H06 locus in hybrids of Solanum lycopersicum and a range of tomato relatives and cultivars depend on the timing of sRNA production and conform to an RNA-directed mechanism. In addition, by scanning the methylomes of tomato introgression lines for shared regions of differential methylation that are absent in the S. lycopersicum parent, we identify thousands of candidate regions for paramutation-like behaviour. The methylation patterns for a subset of these regions segregate with non Mendelian ratios, consistent with secondary paramutation-like interactions to variable extents depending on the locus. Together these results demonstrate that paramutation-like epigenetic interactions are common for natural epialleles in tomato, but vary in timing and penetrance.

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Subcellular Localization of a Plant Catalase-Phenol Oxidase, AcCATPO, from Amaranthus and Identification of a Non-canonical Peroxisome Targeting Signal

Subcellular Localization of a Plant Catalase-Phenol Oxidase, AcCATPO, from Amaranthus and Identification of a Non-canonical Peroxisome Targeting Signal | plant cell genetics | Scoop.it
AcCATPO is a plant catalase-phenol oxidase recently identified from red amaranth. Its physiological function remains unexplored. As the starting step of functional analysis, here we report its subcellular localization and a non-canonical targeting signal. Commonly used bioinformatics programs predicted a peroxisomal localization for AcCATPO, but failed in identification of canonical peroxisomal targeting signals (PTS). The C-terminal GFP tagging led the fusion protein AcCATPO-GFP to the cytosol and the nucleus, but N-terminal tagging directed the GFP-AcCATPO to peroxisomes and nuclei, in transgenic tobacco. Deleting the tripeptide (PTM) at the extreme C-terminus almost ruled out the peroxisomal localization of GFP-AcCATPOΔ3, and removing the C-terminal decapeptide completely excluded peroxisomes as the residence of GFP-AcCATPOΔ10. Furthermore, this decapeptide as a targeting signal could import GFP-10aa to the peroxisome exclusively. Taken together, these results demonstrate that AcCATPO is localized to the peroxisome and the nucleus, and its peroxisomal localization is attributed to a non-canonical PTS1, the C-terminal decapeptide which contains an internal SRL motif and a conserved tripeptide P-S/T-I/M at the extreme of C-terminus. This work may further the study as to the physiological function of AcCATPO, especially clarify its involvement in betalain biosynthesis, and provide a clue to elucidate more non-canonic PTS.
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Phototropin perceives temperature based on the lifetime of its photoactivated state

Phototropin perceives temperature based on the lifetime of its photoactivated state | plant cell genetics | Scoop.it
Living organisms perceive temperature using thermosensory molecules. In this study, we found that phototropin, a blue-light photoreceptor, perceives temperature via a mechanism based on the photoactivated chromophore’s lifetime to induce appropriate chloroplast positioning in plants. Our findings reveal that the chromophore of phototropin directs chloroplast positioning to optimize photosynthesis in plants by (i) sensing blue light and (ii) sensing temperature via a temperature-dependent lifetime mechanism. Because many photoreceptors in a range of organisms contain phtoactivatable chromophores with a thermodependent lifetime, the present study suggests that a common molecular principle underlies biological perception of temperature.
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The P. patens chromosome‐scale assembly reveals moss genome structure and evolution

The P. patens chromosome‐scale assembly reveals moss genome structure and evolution | plant cell genetics | Scoop.it

The draft genome of the moss model, Physcomitrella patens, comprised approximately 2,000 unordered scaffolds. In order to enable analyses of genome structure and evolution we generated a chromosome-scale genome assembly using genetic linkage as well as (end) sequencing of long DNA fragments. We find that 57% of the genome comprises transposable elements (TEs), some of which may be actively transposing during the life cycle. Unlike in flowering plant genomes, gene- and TE-rich regions show an overall even distribution along the chromosomes. However, the chromosomes are mono-centric with peaks of a class of Copia elements potentially coinciding with centromeres. Gene body methylation is evident in 5.7% of the protein-coding genes, typically coinciding with low GC and low expression. Some giant virus insertions are transcriptionally active and might protect gametes from viral infection via siRNA mediated silencing. Structure-based detection methods show that the genome evolved via two rounds of whole genome duplications (WGDs), apparently common in mosses but not in liverworts and hornworts. Several hundred genes are present in colinear regions conserved since the last common ancestor of plants. These syntenic regions are enriched for functions related to plant-specific cell growth and tissue organization. The P. patens genome lacks the TE-rich pericentromeric and gene-rich distal regions typical for most flowering plant genomes. More non-seed plant genomes are needed to unravel how plant genomes evolve, and to understand whether the P. patens genome structure is typical for mosses or bryophytes.

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Identification of a Novel Maize Protein Important for Paramutation at the purple plant1 Locus

Identification of a Novel Maize Protein Important for Paramutation at the purple plant1 Locus | plant cell genetics | Scoop.it
Paramutation occurs at a specific locus when one epiallele, referred to as paramutagenic, facilitates a heritable change in the regulation of the other epiallele, which is referred to as paramutable (reviewed in Arteaga-Vazquez and Chandler, 2010). Because these two states have the same DNA sequence but differ epigenetically, they are referred to as epialleles, or states, rather than alleles. Generally, transcription from paramutable epialleles is heritably repressed following exposure to paramutagenic alleles. Paramutation was first discovered in the 1950s as an epigenetic phenomenon affecting maize (Zea mays) anthocyanin production regulated by red1 (r1) and booster1 (b1). For example, the paramutable B-I epiallele produces strong anthocyanin expression, but when crossed to the low-anthocyanin paramutagenic B′ epiallele, the B-I allele is converted in trans into a heritable, low-anthocyanin, paramutagenic B′ epiallele. Paramutation seems to involve sequences affecting transcription, such as an 853-bp tandem repeat 100 kb upstream of B-I, which acts as a transcriptional enhancer.
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How to get old without aging

How to get old without aging | plant cell genetics | Scoop.it

The low number of mutations in multiple sectors from a 234-year-old oak tree reveals possible mechanisms to avoid the irreversible build-up of mutations in long-lived plants. How do trees manage to survive for hundreds or even thousands of years1,2? How do they avoid the gradual accumulation of mutations due to DNA replication errors and environmental influences such as ultraviolet radiation? In this issue of Nature Plants, Schmid-Siegert et al.3 address this long-standing question by studying genetic diversity in a tree on their campus. The tree is locally known as Napoleon’s Oak and commemorates the visit of the victorious general in the year 1800. Napoleon has been dead now for almost two centuries and so are all his contemporaries, but the oak that bears his name has grown into a magnificent tree. Why do trees live so much longer than us humans? The authors decided to count the number of mutations in Napoleon’s Oak through a great citizens’ outreach project (http://www.napoleome.ch).

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A Review of Biotechnological Artemisinin Production in Plants

A Review of Biotechnological Artemisinin Production in Plants | plant cell genetics | Scoop.it

Malaria is still an eminent threat to major parts of the world population mainly in sub-Saharan Africa. Researchers around the world continuously seek novel solutions to either eliminate or treat the disease. Artemisinin, isolated from the Chinese medicinal herb Artemisia annua, is the active ingredient in artemisinin-based combination therapies used to treat the disease. However, naturally artemisinin is produced in small quantities, which leads to a shortage of global supply. Due to its complex structure, it is difficult chemically synthesize. Thus to date, A. annua remains as the main commercial source of artemisinin. Current advances in genetic and metabolic engineering drives to more diverse approaches and developments on improving in planta production of artemisinin, both in A. annua and in other plants. In this review, we describe efforts in bioengineering to obtain a higher production of artemisinin in A. annua and stable heterologous in planta systems. The current progress and advancements provides hope for significantly improved production in plants.

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Use of CRISPR systems in plant genome editing: toward new opportunities in agriculture

Use of CRISPR systems in plant genome editing: toward new opportunities in agriculture | plant cell genetics | Scoop.it
Initially discovered in bacteria and archaea, CRISPR–Cas9 is an adaptive immune system found in prokaryotes. In 2012, scientists found a way to use it as a genome editing tool. In 2013, its application in plants was successfully achieved. This breakthrough has opened up many new opportunities for researchers, including the opportunity to gain a better understanding of plant biological systems more quickly. The present study reviews agricultural applications related to the use of CRISPR systems in plants from 52 peer-reviewed articles published since 2014. Based on this literature review, the main use of CRISPR systems is to achieve improved yield performance, biofortification, biotic and abiotic stress tolerance, with rice ( Oryza sativa ) being the most studied crop.
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Health effect of agricultural pesticide use in China: implications for the development of GM crops

It is notable that the adoption of GM glyphosate-tolerant crops increases glyphosate use but reduces non-glyphosate herbicide use; and adoption of GM insect-resistant crops significantly reduces insecticide use. While the health hazard of pesticide use has been well documented, little literature evaluates the health effects of different pesticides related to GM crops in an integrated framework. This study aims to associate the uses of different pesticides related to GM crops with the blood chemistry panel and peripheral nerve conduction of Chinese farmers. Pesticides used by farmers were recorded and classified as glyphosate, non-glyphosate herbicides, chemical lepidopteran insecticides, biological lepidopteran insecticides, non-lepidopteran insecticides and fungicides. The multivariate regression results show that none of the examined 35 health indicators was associated with glyphosate use, while the use of non-glyphosate herbicides was likely to induce renal dysfunction and decrease of serum folic acid. The use of chemical lepidopteran insecticides might be associated with hepatic dysfunction, serum glucose elevation, inflammation and even severe nerve damage. In this context, if GM crops are adopted, the alterations in pesticide use may benefit farmer health in China and globe, which has positive implications for the development of GM crops.
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Relaxation of tyrosine pathway regulation underlies the evolution of betalain pigmentation in Caryophyllales

Relaxation of tyrosine pathway regulation underlies the evolution of betalain pigmentation in Caryophyllales | plant cell genetics | Scoop.it
Diverse natural products are synthesized in plants by specialized metabolic enzymes, which are often lineage-specific and derived from gene duplication followed by functional divergence. However, little is known about the contribution of primary metabolism to the evolution of specialized metabolic pathways.
Betalain pigments, uniquely found in the plant order Caryophyllales, are synthesized from the aromatic amino acid l-tyrosine (Tyr) and replaced the otherwise ubiquitous phenylalanine-derived anthocyanins. This study combined biochemical, molecular and phylogenetic analyses, and uncovered coordinated evolution of Tyr and betalain biosynthetic pathways in Caryophyllales.
We found that Beta vulgaris, which produces high concentrations of betalains, synthesizes Tyr via plastidic arogenate dehydrogenases (TyrAa/ADH) encoded by two ADH genes (BvADHα and BvADHβ). Unlike BvADHβ and other plant ADHs that are strongly inhibited by Tyr, BvADHα exhibited relaxed sensitivity to Tyr. Also, Tyr-insensitive BvADHα orthologs arose during the evolution of betalain pigmentation in the core Caryophyllales and later experienced relaxed selection and gene loss in lineages that reverted from betalain to anthocyanin pigmentation, such as Caryophyllaceae.
These results suggest that relaxation of Tyr pathway regulation increased Tyr production and contributed to the evolution of betalain pigmentation, highlighting the significance of upstream primary metabolic regulation for the diversification of specialized plant metabolism.
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Ancient trans-Acting siRNAs Confer Robustness and Sensitivity onto the Auxin Response

Ancient trans-Acting siRNAs Confer Robustness and Sensitivity onto the Auxin Response | plant cell genetics | Scoop.it

Plavskin et al. show that, in moss, ancient TAS3-derived tasiRNAs confer sensitivity
and robustness onto the plant response to the phytohormone auxin and stochastically
modulate development in response to environmental cues. These properties provide a basis for the repeated cooption of small RNA target modules over the course of plant evolution.

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Glyphosate Des voix venues d'ailleurs s'élèvent pour démêler le vrai du faux

Glyphosate Des voix venues d'ailleurs s'élèvent pour démêler le vrai du faux | plant cell genetics | Scoop.it
Alors que le sort du glyphosate sera débattu à la Commission européenne début octobre, forcément les agriculteurs tentent de défendre la première molécule herbicide utilisée en France, pendant que Générations futures, entres autres, multiplie les démonstrations de sa dangerosité. Pour une fois, certains médias "grand public" essaient d'adopter une posture neutre et objective dans le débat.

Via Agriculture Nouvelle
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Identification of a methyltransferase catalyzing the final step of methyl anthranilate synthesis in cultivated strawberry

Identification of a methyltransferase catalyzing the final step of methyl anthranilate synthesis in cultivated strawberry | plant cell genetics | Scoop.it
Methyl anthranilate (MA) contributes an attractive fruity note to the complex flavor and aroma of strawberry (Fragaria spp.), yet it is rare in modern cultivars. The genetic basis for its biosynthesis has not been elucidated. Understanding the specific genes required for its synthesis could allow  the development of gene/allele-specific molecular markers to speed breeding of flavorful strawberries. Ripe fruits from individuals in an F1 population resulting from a cross between a MA producer and a non-producer were examined using a bulk-segregant transcriptome approach. MA producer and non-producer transcriptomes were compared, revealing five candidate transcripts that strictly co-segregated with MA production. One candidate encodes an annotated methyltransferase. MA levels are lower when this transcript is suppressed with RNAi, and bacterial cultures expressing the protein produced MA in the presence of anthranilic acid. Frozen fruit powders reconstituted with anthranilic acid and a methyl donor produced MA only if the transcript was detected in the fruit powder. A DNA-based molecular marker was developed that segregates with the MA-producing gene variant. These analyses indicate that the methyltransferase, now noted ANTHRANILIC ACID METHYL TRANSFERASE (FanAAMT), mediates the ultimate step of MA production in cultivated strawberry. Identification of this gene and its associated molecular marker may hasten breeding efforts to introduce this important volatile into modern cultivars.
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Nanobody‐mediated resistance to Grapevine fanleaf virus in plants

Nanobody‐mediated resistance to Grapevine fanleaf virus in plants | plant cell genetics | Scoop.it

Since their discovery, single-domain antigen-binding fragments of camelid-derived heavy chain-only antibodies, also known as Nanobodies (Nbs), have proven to be of outstanding interest as therapeutics against human diseases and pathogens including viruses, but their use against phytopathogens remains limited. Many plant viruses including Grapevine fanleaf virus (GFLV), a nematode-transmitted icosahedral virus and causal agent of fanleaf degenerative disease, have worldwide distribution and huge burden on crop yields representing billions of US dollars of losses annually, yet solutions to combat these viruses are often limited or inefficient. Here we identified a Nb specific to GFLV that confers strong resistance to GFLV upon stable expression in the model plant Nicotiana benthamiana and also in grapevine rootstock, the natural host of the virus. We showed that resistance was effective against a broad range of GFLV isolates independently of the inoculation method including upon nematode transmission but not against its close relative, Arabis mosaic virus. We also demonstrated that virus neutralization occurs at an early step of the virus life cycle, prior to cell-to-cell movement. Our findings will not only be instrumental to confer resistance to GFLV in grapevine but more generally they pave the way for the generation of novel antiviral strategies in plants based on Nbs.

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Engineered gray mold resistance, antioxidant capacity, and pigmentation in betalain-producing crops and ornamentals

Engineered gray mold resistance, antioxidant capacity, and pigmentation in betalain-producing crops and ornamentals | plant cell genetics | Scoop.it
In plants, three major classes of pigments are generally responsible for colors seen in fruits and flowers: anthocyanins, carotenoids, and betalains. Betalains are red-violet and yellow plant pigments that have been reported to possess strong antioxidant and health-promoting properties, including anticancer, antiinflammatory, and antidiabetic activity. Here, heterologous betalain production was achieved for the first time in three major food crops: tomato, potato, and eggplant. Remarkably, betalain production in tobacco resulted in significantly enhanced resistance toward gray mold (Botrytis cinerea), a plant pathogen responsible for major crop losses. Considering the significant characteristics of these molecules, heterologous betalain production now offers exciting opportunities for creating new value for consumers, producers, and suppliers of food crops and ornamental plants.
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